(a) Field of the Invention
This invention is light-signaling alarm device.
(b) The Prior Art
Public awareness and concern for night safety is increasing . Visibility is a problem for those operating motor-vehicles at night. It is difficult to see pedestrians, bikers, joggers or vice versa. This concern for safety has always curtailed night activities. Therefore, the need to safeguard the public against accidents during night or dark hours has increased dramatically. In the prior art, many safety tips and devices, such as, wearing white clothing has been found to reduce pedestrian's accident probabilities by approximately forty-eight percent (48%). Reflective clothing and tapes have been found to improve the probability that pedestrians will be seen by drivers at night. Swinging a flashlight back and forth will increase visibility as well. Tieing safety reflective lights to a limb of a body, as taught in U.S. Pat. No. 1,594,510. Another U.S. Pat. No. 1,774,457 illustrates the technique of illuminating a roadside sign to respond to vehicle lights at night. Another U.S. Pat. No. 3,893,000 shows the illumination of highway lighting on passing vehicles. Apparatus for both lighting and signaling has been shown in U.S. Pat. No. 4,408,182. Other U.S. Pat. Nos. 4,117,457 and 4,290,047 disclose a system measuring the speed of an incident light source of an approaching vehicle. However prior art lacked the compactness and was ineffective and very expensive to manufacture and maintain. In U.S. Pat. Nos. 4,290,047 and 4,117,457 there is shown system for detecting and measuring the speed of an incident light source. The complexity of this system renders it ineffective and inefficient for use by the general public. For example, Latta's circuits in U.S. Pat. Nos. 4,290,047 and 4,117,457 require two photocell components, a MOSFET transistor, and a Darlington amplifier, several resistive and capacitive components. Also there are digital distance speed logic and display parts. Even without including the so called digital distance, speed logic and display parts, the cost of Latta's circuit is expensive when considering manufacturing cost.
Another deficiency in Latta's circuit design is that the system has two photocell components. One of them (34) is used for detecting an incident light source and another one (42) is included so as to be primarily sensitive to ambient light as shown in FIG. 2 of U.S. Pat. No. 4,290,047 (Latta). But, when the general ambient light levels at least as great as the light incident upon the photocell (34), such as on well lighted streets or parking lots, the resistances of both photocells (34) and (42) become low. In this state, the system consumes power without giving any signals. The reasons of power losses occuring are that low resistances in photocells are the resistance of resistor (44) as well a the interbase resistance of MOSFET. Thus the power of batteries in Latta's circuits (U.S. Pat. Nos. 4,117,457 and 4,290,047) are consumed in an undesirable situation.
The present invention has avoided such drawbacks, which are observed in Latta's circuits and other prior art patents. The purpose of this invention includes a compact device which is easy to operate, cheaper, inexpensive to manufacture, effective and efficient for the general use of the public. This invention, however, is simplified. It only needs one photocell, one IC chip, four resistors, two capacitors, one speaker, one bulb and two switches. The cost of manufacturing is very low. On the other hand, the internal circuit connections and complexities of this new invention are considerably simplified. Again, the reliability of this invention is fairly increased at the same time. It is also part of this new invention to have a variable resistor connected to one photocell and ground to form a voltage divider and adjust the sensitivity of the photocell to avoid power consumption during undesirable situations. By comparison, the prior art including the Latta references (U.S. Pat. Nos. 4,117,457 and 4,290,047) do not have a capacitor for varying the frequency of the amplifier. The only means possible to change the value of the resistance of the photocells (34) or (42) of Latta's circuits is by the light striking those photocells. That is not the case with this new invention where variable resistor R.sub.1 in FIG. I is adjusted to a particular value and is not dependent upon a light striking the photocell (CDS). Another feature in this new invention over Latta's system is a feature that permits independent adjustment of the resistance in the circuit through R.sub.1 in FIG. I, without being interfered with by any change in the amount of light striking the photoresistor. Although this invention is entirely different from Latta's system, the comparisons are made to outline the prior art's flaws, drawbacks and problems. It is part of this invention to alleviate the problems encountered by the public in their search for a better device that would help protect members of the public against accident and crime on the road at night by offering a safety device which operates to provide an audible and visible alarm simultaneously. The differences and improvements made over the prior art references in this new invention can further be explained by again including the fact Latta claimed in his invention that when the variable resistor is also a photo sensitive element, it cannot be adjusted independently of light striking the photo sensitive element. However, with this new invention, it can be adjusted independently. The capacitor C.sub.2 in this new invention has a dual role, because it acts with R.sub.5 to serve as a feedback circuit of the lower circuit network through adjustment, and at the same time provides an integration function that shapes the wave-form with respect to the time of the voltage crossing the lamp (L) and the terminal of the speaker (S). The dual role played by capacitor C.sub.2 which has resulted in allowing the amplifier circuit to provide an integrated voltage with respect to the time of the voltage crossing the lamp (L), and at the same time applied that integrated voltage to the series connected terminal on the speaker (S), the resulting effect will be a clear, distinctive tone with better quality of sound than may be obtained if the speaker S is connected in parallel with the lamp. The preference is for a clear, distinctive and better quality sound generated from the speaker (S) instead of a clicking noise as produced by the prior art references. This new invention allows the speaker and light bulb to operate simultaneously. The Latta references do not teach or suggest the simultaneous operation of the speaker (S) and the lamp (L) nor would it be obvious to one skilled in the art to do so in view of the Latta references. The prior art inventions relate to a measuring device whose variables are the photo-cells and the level of light incident on them. It has a logic board for which the output will result in a distance measurement when calibrated. This present invention is a light-triggered device that turns the oscillators "on" and "off" given several variables such as R.sub.1, R.sub.2, CDS, C.sub.1, C.sub.2, R.sub.3, R.sub.4, R.sub.5 and these variables co- operate by functioning through adjustments to operate both audio and visual warnings simultaneously. This new invention has an amplifier output with an emmiter driver which is not an obvious choice of circuit for even one of ordinary skill in the art. This new invention produces a better quality sound than that produced by the prior art and gives a better response regardless of how it's being carried.